FIG. 1 is a perspective view of an example of a conventional microwave semiconductor device. The device uses a small flat package. FIG. 2 is a plan view of the microwave semiconductor device of FIG. 1 with the package removed. In FIG. 2, a microwave semiconductor element 1 is attached by, for example, soldering, to a die pad 3 of a lead frame 2. The lead frame includes also ground leads 4. The lead frame 2 is formed of, for example, an Fe-Ni alloy.
Ground terminals of the microwave semiconductor element 1 are electrically connected to the die pad 3 and, hence, to the ground leads 4 by bonding wires 5 of, for example, Au bonded to the ground terminals and the die pad 3. Signal terminals of the microwave semiconductor element 1 are electrically connected to signal leads 7 by bonding wires 6 of, for example, Au bonded to the terminals and the leads 7. The signal leads may be also formed of an Fe-Ni alloy, as the lead frame 2. The microwave semiconductor element 1, the die pad 3, and those portions of the ground leads 4 and the signal leads 7 which are adjacent to the die pad 3 are placed in a package 8. The package 8 may be formed of, for example, an epoxy resin.
When the microwave semiconductor device is connected in a microwave circuit (not shown), the ground leads 4 are connected to ground paths of the microwave circuit and the signal leads 7 are connected to signal paths of the microwave circuit.
The ground leads 4 and the signal leads 7 of the above-described conventional microwave semiconductor device function as individual ordinary leads. At high frequencies, the inductance of these leads becomes significant and may degrade the overall characteristic of the microwave semiconductor device.
The present invention provides a microwave semiconductor device free of the above-stated defect present in conventional microwave semiconductor devices. The microwave semiconductor device of the present invention has a characteristic which is not degraded at high frequencies.